gson deserialization to dictionary - deserialization

Question

Json String:
{
"results": [
{
"person": {
"age": 38,
"name": "Ed Helms",
"roles_map": {
"Director": [
{
"id": 336,
"title": "The Office",
"type": "tv"
}
],
"Star": [
{
"id": 336,
"title": "The Office",
"type": "tv"
},
{
"id": 336,
"title": "The Office",
"type": "tv"
}
]
},
"text": "ed-harris"
}
}
]
}
If you see the "roles_map", 'Director' & 'Star' are like keys, which can have array of object as values.
Since keys could be many, I can not make class named Director/Star etc.
I know I should be using Custom Deserializer, but do not know exactly how.
This answer shows what might work, but I could not make it work.
Update:
If I do simple gson.fromJson(str, RootObject) it will work. But since Director/Star are the roles, so thats data and not the class. And there could be many more roles. So I need way to put those roles into dictionary rather than classes.
Working Classes:
class Director
{
public int id ;
public String title ;
public String type ;
}
class Star
{
public int id ;
public String title ;
public String type ;
}
class RolesMap
{
public List<Director> Director ;
public List<Star> Star ;
}
class Person
{
public int age ;
public String name ;
public RolesMap roles_map ;
public String text ;
}
class Result
{
public Person person ;
}
class RootObject
{
public List<Result> results ;
}
Expected Classes:
class Show
{
public int id ;
public String title ;
public String type ;
}
class Person
{
public int age ;
public String name ;
public HashMap<String, Show[]> RolesMap;
public String text ;
}
class Result
{
public Person person ;
}
class RootObject
{
public Result[] results ;
}